Can someone help out a new player with answering questions for me?

I am currently playing a fire witch and I really like it. I am relatively new to poe and I like to plan ahead. Here are some questions I would like answered if someone has time.

1. What is the end game like?
2. What are some builds that are fun and do lots of damage and I can do fast clears?
3. What should I want on my gear Stat wise?
4. What are some of the abbreviations on reddit that are mostly used?
5. As I level, what should I be saving for end game?
6. Finally, what is the trial quest for where I have to complete 6 trials?